Most earlier theoretical studies on turbulent dynamo focused on its kinematic regime with
negligible magnetic back reaction
[1]}, [2]}, [3]}, [4]}, [5]}.
For the kinematic regime of dynamo, the dynamo growth of magnetic fields and the magnetic field structure are
sensitive to the plasma parameters,
including both the ionization fraction
[3]}, [7]}
and the magnetic Prandtl number
[8]}, [9]}.
For astrophysical settings involving large length scales and long timescales,
the kinematic dynamo alone is insufficient to explain the
dynamo evolution of magnetic fields and their dynamical roles in the multi-scale astrophysical processes.
With the growth of magnetic energy, the magnetic back reaction on turbulence becomes significant
and the dynamo enters the nonlinear regime.
Numerical simulations
reveal that the dynamo in the nonlinear regime has distinctive characteristics
[10]}, [11]}, [12]}, [13]}, [14]}.
Instead of an exponential growth of magnetic energy,
the magnetic energy grows linearly with time with an inefficient dynamo growth rate.
The resulting magnetic energy spectrum peaks at a large length scale instead of the resistive scale
as for the kinematic dynamo
[11]}, [16]}.
